Tribology and Airborne Particle Emission of Laser-Cladded Fe-Based Coatings versus Non-Asbestos Organic and Low-Metallic Brake Materials

Yezhe Lyu,Mara Leonardi,Jens Wahlström,Alessandro Mancini,Ulf Olofsson

doi:10.3390/met11111703

Yezhe Lyu, Mara Leonardi + Show 3 more

Open Access

https://doi.org/10.3390/met11111703

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Abstract

Laser cladding is a promising surface treatment for refurbishing worn-out cast-iron brake rotors. Previous studies on laser-cladded brake rotors have demonstrated their extensively higher wear and greater airborne particle emissions, compared with traditional cast iron rotors. In order to overcome this, a commercial non-asbestos organic (NAO) brake material is tested against Fe-based laser-cladded and traditional cast-iron brake rotors. Two low-metallic brake pad materials are also tested as references. The materials’ coefficients of friction, specific wear rates and particle number concentrations are evaluated. The results indicate that the NAO brake material showed lower wear and had fewer particle emissions than the low-metallic brake materials when deployed against both cast iron and laser-cladded brake rotors. The NAO/laser-cladding friction pairing showed wear, particle concentration and fraction of fine particles (sub 1 μm) equivalent to those of the low-metallic/cast-iron friction pairing, creating significant potential for application in refurbishing worn-out cast-iron brake rotors.

Highlights

A brake rotor is a crucial component in an automotive disc-brake system that slows a vehicle by friction with its brake pads
This less-aggressive wear can be identified in the scanning electron microscope (SEM) micrographs presented in Figures 4 and 5, where less-aggressive wear is noticeable for the discs run against the non-asbestos organic (NAO) pad material as compared to the semi-metallic Cu-free one
A pin-on-disc tribometer study was conducted to evaluate the coefficient of friction

Summary

Introduction

A brake rotor is a crucial component in an automotive disc-brake system that slows a vehicle by friction with its brake pads. Different attempts have been made to combat these deficiencies One such strategy is the application of alternative materials to replace GCI in producing automotive brake rotors. Such alternative materials include metal matrix composites [2] and ceramic matrix composites [3], but these materials are more expensive than GCI, and, are not suitable for commercial use in automotive brake rotors. Another strategy is to overlay a protective coating on the GCI substrate. This method is encouraging, since it is suitable for producing brand-new brake rotors, and capable of refurbishing worn brake rotors

Results

Discussion

Conclusion